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H. E. ANTHONY INSPECTION COVER Filed May 1, 194e an, me.

Patented ug. 30, 1949 UNITED STATES ement INSPECTION cov-ER Howard Anthony, netten Batter, d Applieationiviay A1v, 1946,:seria1 No. 666,369

'This invention .relates to inspection covers fand more particularly to the provision of covered spection and access openings in the skin coverings of aircraft lor the like. 4In 'airplanes it has been customary to .provide inspection and access openings at various points in the fuselage or wings and to coversuch openings with removable covers. As heretofore constructed, suchfcove'rs particularly as used on small fabric covered aircraft have been provided with springs extending beyond the edges of 'the cover disc to slide over the edges o'f the -opening and secure the cover disc pljace. Such covers are d-iflicul-t to remove and replace and -to maintain in proper position over the Loj'perrmg,

The present invention has for its objects to provide inspection covers which may be easily removed and replaced, preferably by turning, which are accurately located over the openings when in place, and which are securely held against accidental removal.

The above and other objects and advantages of the invention will be more readily apparent from the following description when read in connection with the accompanying drawing, in which- Figure 1 is an elevation View of an inspection cover embodying the invention in place;

Figure 2 is a section on the line 2--2 of Figure 1;

Figure 3 is a section on the line 3-3 of Figure 1;

Figure 4 is an elevation of the reinforcing ring; and

Figure 5 is a perspective view of one of the fastening springs.

The cover as illustrated is adapted to cover an opening in the fuselage or wing of an aircraft having a fabric skin covering I treated in the usual manner with lacquer or the like to make it water and air tight. The skin covering II) is formed with a circular opening therein for inspection and access purposes, such openings being located at any desired points in the aircraft skin cover. According to the present invention the skin covering is reinforced around the opening by a flat annular ring II which is preferably formed of plastic material whose composition is similar to that of the coating on the fabric. The inner edge of the ring is cut out at a plurality of spaced points to form notches I2 as best seen in Figure 4. The riny formed as shown may be securely fastened to the skin covering by treating it with a solvent for the lacquer material so that it will be securely cemented to the skin covering. 'I'his is preferably done before the open- 4 claims. (C1. "2M-129) 2. ing is cut in the skin .-coveri-ng, the skin being eut out from the interior of the ring and from the notches I2 fafter the rin-g has been secured in place.`

The cover proper comprises a disc i3 preferably formed of thin light Weight metal of slightly larger diameter than ythe ring Ii and turned up at vits edges as indicated at yfI 4 `to Iii-t over 'the yedges of the ring. To hold the 'disc -I 3--ir1 pl-ace apair of leaff springs le are secured tothe inner side-thereef by rivets or the llike IE. The rivets QI@ engage the springs adjacent the central 4portions to leave their ends free, as shown, and the spring-sare of a -iength less than thje vd-i-aifrieter of the disc and preferably approximately equal to the space across diametrically opposite notches I2. Preferably the ends of the springs are twisted slightly as indi cated at I6 in Figure 5 so that the springs may ride more easily over the edges of the notches l2 in attaching the disc to the ring.

With the construction shown the disc is adapted to be rotated partially for both attaching it to and detaching it from the ring. To facilitate this operation the disc may have two or more recesses II pressed therein to receive te lingers of an operator so that he can turn the disc easily. In attaching the disc it is laid against the ring with the ends of the springs lying in the notches I2 and is then turned to cause the ends of the spring to ride over the notches and engage the inner surface of the skin covering as shown in Figure 2.

In order to locate the cover disc accurately over the opening an annular ridge I8 is preferably pressed up from the inner side thereof and is of a diameter to fit within the inner edge of the ring Il. In tlr's way the disc is accurately located with respect to the reinforcing ring so that it will at all times properly cover the opening. Instead of a complete annular ridge it will be understood that a series of spaced projections to engage the inner edge of the ring could be used to locate the disc equally well.

Accidental removal of the disc from the reinforcing ring is prevented by inwardly extending projections IQ formed on the disc between the ends of the springs and so located as to enter the notches I2 when the disc is turned. When the disc is initially placed on the ring the projections I9 will ride over the inner surface of theV ring or of the skin covering until the ring has been turned approximately At this time the projections I9 will drop into the notches I2 to hold the disc against further accidental turning.

While one embodiment of the invention has 3 been shown and described herein in detail. lt will be understood that this is illustrative only and is not to be taken as a definition of the scope of the invention, reference being had to the appended claims for this purpose.

What is claimed is:

1. An inspection cover for aircraft and the like and adapted to overlie a circular opening having a plurality of diametrically opposed notches on its inner edge, comprising a disc larger than the opening, a pair of crossed springs secured in their central portions to one side of the disc and shorter than the diameter of the disc whereby their ends can enter said notches, the disc having depressed recesses therein to receive the fingers of an operator for turning the disc and having projections on said one side between the ends of the springs to enter said notches and prevent the disc from turning.

2. An inspection cover for aircraft and the like comprising a disc adapted to overlie an opening smaller than the disc and having diametrically opposed notches on its inner edge, the disc having a raised annular ridge on one side to t into the opening, a leaf spring extending across said one side of the disc and secured in its center portion to the disc, the ends of the spring being adapted to enter said notches in the edge of the opening, and the disc having depressed recesses in its other side to receive the fingers of an operator for turning the disc and having projections on said one side adjacent its edge to enter said notches when the disc is turned.

3. An inspection cover for aircraft and the like comprising an annular ring to be secured around an opening in an aircraft skin having a plurality of diametrically opposed spaced notches on its inner edge, a disc to ilt over the ring, a pair of crossed leaf springs secured at their central parts to one side of the disc vso that their ends can enter the notches in the ring, and the disc having recesses in its other side to receive the ngers of an operator for turning the disc, and having raised projections on said one side between the ends of the springs to fit into the notches when the disc is turned.

4. An inspection cover for aircraft and the like adapted to overlie a circular opening having a plurality of notches on its inner edge, comprising a disc larger than the opening, a plurality of leaf springs attached to one side of the disc and shorter than the diameter thereof and disposed to be received in said notches, said disc having elongated projections on said one side and positioned between the ends of said springs to be received in said notches.

HOWARD E. ANTHONY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATESV PATENTS Number Name Date 1,907,546 Jarvis May 9, 1933 2,316,507 Dykeman Apr. 13, 1943 2,383,200 Kramer et al Aug. 21, 1945 

